UK Mini Mitral trial

Minimally invasive thoracoscopically-guided right minithoracotomy versus conventional sternotomy for mitral valve repair: a multicentre randomised controlled trial (UK Mini Mitral).

Heart surgery to repair one of the valves in the heart (the mitral valve) is commonly performed in the NHS. Patients needing this operation sometimes suffer symptoms of shortness of breath (especially when exercising), tiredness, and swollen ankles, caused by the valve becoming leaky (mitral regurgitation). Some patients suffer very few symptoms.

These patients are quite often of working age so time away from their place of work can be difficult for a number of reasons. We need to make sure that the operations offered within the NHS are best for patients.

To repair the valve, the operation usually involves cutting the breastbone completely (from the collar bone to the bottom of the breastbone); this is called a sternotomy. An operation has been developed which means that the valve can be repaired using a much smaller cut on the side of the chest; this operation is called a mini-thoracotomy.

The trouble is, we don’t know which operation is better for patients and for the NHS because there is no good research to show what effects two different types of surgery to access the heart and repair the valve have on patients.

We have spoken to heart doctors and heart surgeons in the UK and the USA as well as to patients who have had each of these types of surgery, and to patients waiting for surgery. They all think it is important that we know which operation enables patients to return to normal activities sooner after the operation on their mitral valve.

This study will compare the two operations in 400 adult patients, to see how well they recover and return to normal activities. The trial will include patients at NHS hospitals across England and Scotland. Patients will be randomised (allocated) to undergo one of the operations. The trial is large enough to show which operation is better for patients and the NHS.

We will ask patients who take part questions about their physical activities and quality of life before and after their operation. We will also check other important factors to see how well patients recover, including how well their valve works up to twelve weeks and twelve months after surgery using a heart scan (called an echocardiogram). We will ask patients to wear a device that measures their activity for one week on seven occasions; the device looks like a wrist-watch and can be worn all day and all night. Any complications following a patient’s operation will be recorded from their medical records.

We will also calculate the costs of care for each operation by looking at medical records to see how often patients are seen in hospital after their operation. Patients who take part will attend hospital a few times in the first year, after this we will continue to check their progress by reviewing their medical notes. We will ask patients to confirm that they are happy that we keep looking at their medical records, even after the trial is finished.

Please see our website:

Principal investigator

Mr Enoch Akowuah

Consultant Cardiothoracic Surgeon,

South Tees Hospitals NHS Foundation Trust


Tel: 01642 850850 ext 53922

Lead nurse

Karen Ainsworth

Lead Research Nurse


Tel: 01642 854 321

Clinical trials unit:

Newcastle Clinical Trials Unit
Faculty of Medical Science
Newcastle University
Tel: 0191 208 2522

Sponsor: South Tees Hospitals NHS Foundation Trust


Funding Acknowledgement: This project was funded by the National Institute of Health Research – Health Technology Assessment Programme (project reference 14/192/110)

Department of Health Disclaimer:
The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the HTA, NIHR, NHS or the Department of Health.